JPS62132283A - Test method for magnetic heads - Google Patents

Abstract

PURPOSE:To correct the upper limit value and the lower limit value of a fitting height by providing a sensor to detect an impact wave occurring due to the contact with a magnetic head and magnetic recording medium, changing the fitting height of the magnetic head and detecting a contact impact wave. CONSTITUTION:When a slider S is brought into contact with a rotating disk D, an impact wave is detected by an AE sensor F, and therefore, an impact detecting signal is amplified by an amplifier K, the impact detecting signal is amplified by an amplifier K, the impact detecting signal is measured by a measuring device and the rotating disk D is decided to contact with the slider S. Consequently, for an arm, when the fitting height is changed, it can be confirmed by the output signal of the AE sensor F that in the upper limit value and the lower limit value, the slider S is brought into contact with the disk D. Thus, the test method of a floating margin to assure then floating of a magnetic head can be obtained.

Description

[Detailed Description of the Invention] [Summary] An AE (acoustic emission) sensor is installed to detect a crash with a magnetic medium during the operation of a flying magnetic head, and the flying margin of the magnetic head is determined from the output of this AE sensor. Measure.

[Industrial application field]

The present invention relates to a method for testing a magnetic head, and more particularly to a method for testing a flying margin of a magnetic head.

A floating magnetic head (hereinafter referred to as a head) floats above a moving magnetic recording medium (hereinafter referred to as a medium) and magnetically writes information onto the medium or reads information recorded on the medium. It is configured.

If the head comes into contact with the media during media travel, damage to the head and media will occur.

Therefore, it is necessary to perform a 9M1 design so that the head is held in a flying state with respect to the traveling medium, and to have an efficient test method to guarantee a predetermined head flying margin.

[Conventional technology]

FIG. 4 shows a sectional view of essential parts of a conventional magnetic disk device.

A slider s4 floats hydrodynamically on a rotating magnetic disk D (hereinafter referred to as disk),
The slider S is swingably attached to the gimbal J via the piposo I-P.

The gimbal J is fixed to the arm A, and the arm A is moved in the radial direction of the disk D by a drive section G, so that the disk D is accessed.

L is the mounting height of arm A, and considering the design error of the magnetic disk device and the mounting error of arm A, it is desirable to secure a large height margin for mounting around the design value L0.

If the gimbal is bent or there is an abnormality in the coupling state between the slider and the gimbal, stable flying over the medium cannot be guaranteed.

For this reason, conventionally, defects such as bending of the gimbal or abnormality in the coupling state between the slider and the gimbal have been visually inspected.

[Problems to be solved by the invention] In this conventional method, defects may be overlooked because the gimbal is visually inspected, and the mounting state, such as the degree of deformation of the arm that occurs when the gimbal is actually attached to the arm, must also be visually inspected. It is difficult to do so, and it is also undesirable in terms of labor and efficiency.

The present invention has been made in view of the above, and an object of the present invention is to provide a method for testing a flying margin that guarantees flying of a magnetic head.

[Means for solving problems]

FIG. 1 is an explanatory diagram of the principle of the present invention, and parts equivalent to those in FIG. 4 are given the same reference numerals.

F is an AE sensor, an amplifier that amplifies the output signal of the AE sensor F, and G is a drive section.

The gap portion H is in contact with the rotating disk D.

[For production]

When the slider S comes into contact with the rotating disk D, a shock wave is detected by the AE sensor F, so the shock detection signal is amplified by an amplifier, the shock detection signal is measured by a measuring device (not shown), and the shock wave is detected by the AE sensor F. It turns out that the rotating disks D came into contact (collided).

Therefore, when the mounting height of the arm is changed, it can be confirmed by the output signal of the AE sensor F that the slider S contacts the disk D at its upper and lower limits.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Figure 2(a) is a diagram in which the height LI41 of the arm A is set higher than the reference value L0.The spring pressure due to the bending part AM of the head H is smaller than the design value, but the height LI41 is higher than the reference value L0. It floats in hydrodynamic balance with the airflow generated by rotation.

Therefore, the AE sensor F does not output a shock wave detection signal.

From this state, install the arm by increasing the height further to LH2.
Then, as shown in the same figure (bl), the slider S attached to the pivot P is released from hydrodynamic balance,
The back surface N of the slider S forms an inclination angle α. As a result, the slider S and the disk D come into contact, and at this time a shock wave is detected by the AE sensor F, and the detection signal is amplified by an amplifier and recorded by a measuring device.

In Figure 2 (C), arm A is installed using the height as a reference value.

In this figure, the bent part AM is bent in a downwardly protruding manner on the rotating disk D, contrary to the figure (a), and the spring pressure is greater than the design value, causing it to float. However, if the hydrodynamic balance is maintained, the slider S will float, and the AE sensor F will not output a shock wave detection signal.

If the installation height of arm A is further lowered from this state, the spring pressure of bending part AM becomes stronger than the floating blade of slider S, and slider S comes into contact with disk D, so AE sensor F
A shock wave detection signal is output from.

FIG. 3 is a diagram showing the relationship between the arm mounting height obtained in this way and the output level Q of the AE sensor F.

The solid line in the same figure indicates the attachment of the head arm A described in connection with FIG.
It is an output waveform diagram of E-sensor F, showing characteristics as designed values.

The broken line in the figure indicates that the flying height of the slider S is low, and if the arm mounting height is lowered by ΔL1 from the reference value L0, the slider S
This shows that the disk D is in contact with the disk D.

In addition, the dashed line in the same figure shows that when the arm is installed, the slider S and disk D come into contact when the height becomes ΔL2 higher than the reference value L0, and on the other hand, the slider S and the disk D contact each other until the arm installation height becomes ΔL3 lower than the reference value L0. This indicates that the disk D does not make contact.

〔Effect of the invention〕

As described above, the magnetic head testing method according to the present invention includes a sensor that detects the shock wave generated by contact between the magnetic head and the magnetic recording medium, changes the mounting height of the magnetic head, and measures the contact between the magnetic recording medium and the magnetic head. The magnetic head installation measures the upper and lower limits of the height by detecting the contact shock waves generated between the magnetic head and the magnetic recording medium. value and lower limit value can be measured accurately.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention, FIG. 2 is a diagram explaining the test method of the present invention, FIG. 3 is a diagram showing the test results, and FIG. It is a partial sectional view. P: Pivot, J Nishin Pal, S Nishin Pal, A: Arm, F: AE sensor, D: Disk, K: Amplifier, G:
Drive part. Figure 1: Diagram showing test results Figure 3: P: Piho 0. Figure 2 clarifies the method of testing for acuity.

Claims (1)

[Claims] A magnetic disk device using a floating magnetic head, comprising a sensor for detecting a collision between the floating magnetic head during operation and a recording medium having an information recording area accessed by the magnetic head. , the relative height between the recording medium surface and the magnetic disk is changed, the collision is detected by the sensor, and an allowable relative height range between the recording medium surface and the magnetic disk is tested. Test method for magnetic heads.